{{db-multiple|U5|G11}}
{{Infobox software
| name =
| logo = 
| Author = [https://en.wikipedia.org/wiki/Aaron_Swartz Aaron swartz]
| released = 
| latest release version = web.py-0.37
| latest release date = 
| size = {{nowrap|88 [[kilobyte|KB]]}}
| status = Active
| programming language = Python
| Type = Web application Framework
| website = {{webpy.org}}
}}

Web.py is a [[free and open source]] [[Web application framework]] that is as simple as it is powerful.

The web.py slogan is: "Think about the ideal way to write a web app. Write the code to make it happen."<ref>{{Cite web|title = web.py official website|url = http://webpy.org/|website = web.py}}</ref>. The goal of web.py is to build the ideal way to make web apps. web.py allows the user to build [[HTTP]] responses instead of exposing [[Python]] objects. In web.py, [[database]] can be accessed easily as the framework makes database look like an [[object (computer science)|object]]. Also, the template system in web.py helps the user to bring Python into [[HTML]]<ref>{{Cite web|title = web.py philosophy|url = http://webpy.org/philosophy|website = web.py philosophy}}</ref>. "It's the anti-framework framework. web.py doesn't get in your way." explained founder Steve Huffman.

Some of the [[websites]] which uses web.py are
* [http://frinki.com/ Frinki], a new social network in spanish.
* [http://www.oyster.com/ oyster.com], a website that reviews hotels uses web.py for the entire website.
* [http://makehistory.national911memorial.org/ Make History], a project of the 9/11 memorial museum.

=='''History'''==

web.py was originally published while [[Aaron swartz]] worked at [http://reddit.com/ reddit.com], where the site used it as it grew to become one of the top 1000 sites according to [http://www.alexa.com/topsites/global;1 Alexa] and served millions of daily page views<ref>{{Cite web|title = Aaron swartz about web.py|url = http://www.aaronsw.com/weblog/rewritingreddit}}</ref>. The site was rewritten using other tools after being acquired by Condé Nast.

=='''Why Web.py?'''<ref>{{Cite web|title = Python development story, Why web.py?|url = http://faruk.akgul.org/blog/python-development-story-why-webpy/|website = why web.py}}</ref>==

The reasons for using web.py are
* Simplicity
* Freedom
* Writing clean code
* Minimalism
* A solid web framework

=='''Installation'''<ref>{{Cite web|title = web.py Installation|url = http://webpy.org/|website = Installation of web.py in linux}}</ref>==
To install web.py on Linux based operating system,
* Firstly, download the following tar file:
wget http://webpy.org/static/web.py-0.37.tar.gz
* Extract the downloaded tar file:
tar -zxvf web.py-0.37.tar.gz
* Go to web.py-0.37 directory:
cd web.py-0.37/
* Install and make it accessible to all the applications:
sudo python setup.py install

=='''Web.py skeleton'''<ref>{{Cite web|title = web.py GitHub|url = https://github.com/webpy/webpy|website = web.py github}}</ref>==

Every web application needs a skeleton. A sample skeleton of web.py application looks as follows.

* doc: Documentation of all the files.
* licenses: All the licenses of the project and the libraries used in the application.
* requirements: Specifying the third party libraries.
* sh: bash script files of the project.
* [[www]]: The required web application itself.
** app: contains the application modules.
*** [http://stackoverflow.com/questions/1015813/what-goes-into-the-controller-in-mvc controllers]: This module contains the handler modules of controller package.
*** tools: Tools that are used for the project.
*** [http://betterexplained.com/articles/intermediate-rails-understanding-models-views-and-controllers/ views]]: Template files.
*** [http://betterexplained.com/articles/intermediate-rails-understanding-models-views-and-controllers/ models]: Database models of the application.
*** bridge: It is used to communicate with the server which is written in another language.
** lib: The library files developed for the project. These are different from the tools mentioned in the app. Libraries can be used in other projects where as tools are limited to the project itself.
** public: This folder contains the minimized compiled [[CSS]], [[Javascript]], [[CoffeeScript]] files and images so the files in this folder are production ready and can't be used in development.
** static: Contains the development CSS, CoffeeScript, Javascript, and images files of the project.
** test: These are the test files.
** tmp: Garbage files.
** main.py: These are the only files that are directly executed by the server.
** main_development.py: Main executable file in development mode.
** settings.py: Global constants and settings of the application.
** urls.py: Contains [[URL]]'s of the application

=='''Features of web.py'''==

''web.py has two unique features''

===Databases<ref>{{Cite web|title = web.py Databases|url = http://webpy.org/cookbook/select|website = web.py Database db.select}}</ref>===

The database package lets the user access various different databases. Accessing different databases refers to connecting multiple databases. However, its not an [[ORM]]. It is similar to sqlite3 package which doesn't use ORM. This feature is missing in [[Django]] (another web framework). web.py has flexible modules which allow the user to wipe it out completely and use with another web framework.
Before creating database object, the user must install appropriate database library like psycopg2 for [[PostgreSQL]], MySQLdb for [[MySQL]] and sqlite3 for [[SQLite]]. Working with more databases is not at all difficult with web.py which is explained by the following example:
<pre>
db1 = web.database(dbn='postgres', db='dbname1', user='username1', pw='password2')
db2 = web.database(dbn='postgres', db='dbname2', user='username2', pw='password2')
</pre>

===Forms<ref>{{Cite web|title = web.py Forms|url = http://webpy.org/cookbook/forms|website = Usage of forms in web.py}}</ref>===

A forms package is present in web.py which let's the user create forms and [https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/Forms/Data_form_validation validators]. The form module of web.py allows the ability to generate html forms, get user input, and validate it before processing it or adding it to a database. But it doesn't have built-in protection against [[CSRF]]. A sample login form is as follows:
<pre>
login = form.Form(
form.Textbox('username'),
form.Password('password'),
form.Button('Login'),
)
</pre>

Another interesting feature about web.py is its flexibility. It has flexible modules which can be used with another framework.

=='''Hello world example'''==
<pre>
import web
urls = (
'/', 'index'
)

class index:
def GET(self):
return "Hello, ECE517!"

if __name__ == "__main__":
app = web.application(urls, globals())
app.run()
</pre>

If the above example is considered, then the user start the application by importing the web.py module using the following command
import web

The most important part of the website is its URL structure. web.py makes it easy to make great URLs.

<pre>
urls = (
'/', 'index'
)
</pre>

The first part is a [[regular expressions]] that matches a URL, like /, /help/faq, /item/, etc. The parentheses say to capture that piece of the matched data for use later on. The second part is the name of a class to send the request to, like index, view, welcome, hello (which gets the hello ECE517 of the welcome module), or get_\1. \1 is replaced by the first capture of the regular expression; any remaining captures get passed to function.<ref>{{Cite web|title = web.py Hello world example|url = http://webpy.org/docs/0.3/tutorial|website = Web.py example tutorial}}</ref>

At the top of each application, the user usually see the full URL dispatching scheme defined as a tuple.
<pre>
urls = (
"/tasks/?", "signin",
"/tasks/list", "listing",
"/tasks/post", "post",
"/tasks/act", "actions",
"/tasks/signup", "signup"
)
</pre>
The format of this tuple is: url-path-pattern, handler-class this pattern will repeat as more url patterns are defined.

=='''Conclusion'''==

web.py is a minimalist framework whose aim is not to abstract away the details of interacting with the Web, but to make that interaction easier. It is designed in such a way that user will get started quickly with web.py and find writing [http://www.w3schools.com/tags/ref_httpmethods.asp HTTP GET] function handlers directly<ref>{{Cite web|title = comparison of frameworks|url = http://www.infoworld.com/article/2622836/application-development/pillars-of-python--six-python-web-frameworks-compared.html?page=2|website = Comparison of different python web frameworks}}</ref>. Likewise, the web.py database system does not abstract away [[SQL]] rather than hide the fact that the user is querying a database. It hides the details of working with different databases. The framework of web.py is light, photonic when compared to frameworks like [[flask (web_framework) | flask]].

=='''See Also'''==
[[Django]]

[[Bottle (web framework) | Bottle]]

=='''References'''==

=='''Wiki write up'''==

About Review mapping controller

/* When a reviewerreport reviews, assigning reviews and quizzes to teams. It also contains methods to assign reviews to participants automatically*/ Ignore this

Review mapping controller contains methods related to peer reviewing strategies. It contains methods to add a reviewer, delete a reviewer, selecting a reviewer. Depending on the number of students and number of submissions, the topics to be reviewed are assigned to the students automatically. If a user wants to look for the submission team , it returns the team by comparing the submission id's with the team id's. Also, it assigns quizzes dynamically. Generation of review report, feedback report and teammate review is done.

==='''Code Improvements'''===

1. Unused variables and arguments: There are unused variables in the methods. If there are unused variables in the methods, it uses stack unnecessarily. So, it is better to remove the unused variables.

When both keys and values are not used, but given as arguments, then the used variables can be added "_" or replaced with "_" to represent it as unused variable but allowed in the arguments.

<pre>
At line 533 and line 539
Previous Code: teams_hash = unsorted_teams_hash.sort_by{|k, v| v}.to_h
After Changing the code: teams_hash = unsorted_teams_hash.sort_by{|_, v| v}.to_h
</pre>

2. Use sample instead of shuffle
When sample is used, the elements are chosen by using random and unique indices in the array so that the elements doesn't repeat in the array. This cannot be guaranteed in shuffle.

<pre>

Previous Code:
assignment_team = assignment_teams.to_a.shuffle[0] rescue nil

topic = assignment.candidate_topics_to_review(reviewer).to_a.shuffle[0] rescue nil

After Changing the code:

assignment_team = assignment_teams.to_a.sample rescue nil

topic = assignment.candidate_topics_to_review(reviewer).to_a.sample rescue nil
</pre>

==='''Testing UI'''===

Peer review insformation:
* Instructor Login:
Username: Instructor6
Password: password
* Student login:
Username: Student6384
Password: password

User:Ndhanir

2016-03-31T05:17:06Z

Ndhanir: /* Wiki write up */

CSC/ECE 517 Spring 2016/Refactor review mapping controller.rb

2016-03-24T03:41:04Z

Ndhanir: /* Code Improvements */

==E1615. Refactoring the Review Mapping Controller==

This page provides details about the OSS project which was based on refactoring one of controllers related to peer reviewing strategies used in Expertiza.

__TOC__

=='''About Review mapping controller'''==

Review mapping controller contains methods related to peer reviewing strategies. It contains methods to add a reviewer, delete a reviewer, selecting a reviewer. Depending on the number of students and number of submissions, the topics to be reviewed are assigned to the students automatically. If a user wants to look for the team for a submission , it returns the team by comparing the submission id's with the team id's. Also, it assigns quizzes dynamically. Generation of review report, feedback report and teammate review is done.

=='''Code Improvements'''==

==='''Unused variables and arguments'''===

There are unused variables in the methods which use the stack unnecessarily. So, it is better to remove the unused variables or at the least indicate that a variable is unused.

For suppose when both keys and values are not used in a hash but are given as arguments, then the unused variables can be indicated by adding a "_" infront of the name or replace the unused variable with "_" to represent it as unused variable but allow them in arguments.

<pre>
Previous Code: teams_hash = unsorted_teams_hash.sort_by{|k, v| v}.to_h
</pre>
<pre>
After Changing the code: teams_hash = unsorted_teams_hash.sort_by{|_, v| v}.to_h
</pre>

In the above case teams_hash should consist of a hash with both keys and values but the sorting is done based on values. So the key is replaced with a "_" so that the user may deem it unused in the implementation of the process.

==='''Use sample instead of shuffle'''===

When sample is used, the elements in an array are chosen by using random and unique indices in the array so that the elements doesn't repeat in the array. This cannot be guaranteed in shuffle. Also by using shuffle[0] we are shuffling all the elements in the array and then picking the first element instead of picking a single element randomly which is more efficient. The following are the couple of places where shuffle[0] was used and is replaced by sample.

<pre>
Previous Code:

assignment_team = assignment_teams.to_a.shuffle[0] rescue nil

topic = assignment.candidate_topics_to_review(reviewer).to_a.shuffle[0] rescue nil
</pre>
<pre>
After Changing the code:

assignment_team = assignment_teams.to_a.sample rescue nil

topic = assignment.candidate_topics_to_review(reviewer).to_a.sample rescue nil
</pre>

==='''Cyclomatic complexity of automatic_review_mapping_strategy method'''===

The method automatic_review_mapping_strategy handles the number of reviews assigned to a individual and also the number of reviews that can be done with in a team. The method is very long and has many nested if statements due to which the complexity of the method is very high. Instead of a single method handling all the parts of the strategy, it is divided into several parts due to which the code is more readable and also the complexity of code is shared by each method.

The method first checks the number of participants that are in an assignment and the number of teams that are present. It then sets the values for the maximum number of reviews that are possible and also the minimum number that are required. Then it assigns the reviews to each of the teams randomly when a request for review is made by a participant. At last it checks if the participant has the minimum number of reviews required after allotting the reviews. If not, it assigns more reviews to valid teams so that the minimum requirement is met.

The part of the code that is moved out of automatic_review_mapping_strategy as peer_review_strategy:

<pre>
private
def peer_review_strategy(teams, num_participants, student_review_num, participants, participants_hash)
iterator = 0
teams.each do |team|
selected_participants = Array.new
if !team.equal? teams.last
#need to even out the # of reviews for teams
while selected_participants.size < num_reviews_per_team
num_participants_this_team = TeamsUser.where(team_id: team.id).size
#If there are some submitters or reviewers in this team, they are not treated as normal participants.
#They should be removed from 'num_participants_this_team'
TeamsUser.where(team_id: team.id).each do |team_user|
temp_participant = Participant.where(user_id: team_user.user_id, parent_id: assignment_id).first
num_participants_this_team -= 1 if temp_participant.can_review == false or temp_participant.can_submit == false
end
#if all outstanding participants are already in selected_participants, just break the loop.
break if selected_participants.size == participants.size - num_participants_this_team

# generate random number
if iterator == 0
rand_num = rand(0..num_participants-1)
else
min_value = participants_hash.values.min
#get the temp array including indices of participants, each participant has minimum review number in hash table.
participants_with_min_assigned_reviews = Array.new
participants.each do |participant|
participants_with_min_assigned_reviews << participants.index(participant) if participants_hash[participant.id] == min_value
end
#if participants_with_min_assigned_reviews is blank
if_condition_1 = participants_with_min_assigned_reviews.empty?
#or only one element in participants_with_min_assigned_reviews, prohibit one student to review his/her own artifact
if_condition_2 = (participants_with_min_assigned_reviews.size == 1 and TeamsUser.exists?(team_id: team.id, user_id: participants[participants_with_min_assigned_reviews[0]].user_id))
if if_condition_1 or if_condition_2
#use original method to get random number
rand_num = rand(0..num_participants-1)
else
#rand_num should be the position of this participant in original array
rand_num = participants_with_min_assigned_reviews[rand(0..participants_with_min_assigned_reviews.size-1)]
end
end
# prohibit one student to review his/her own artifact
next if TeamsUser.exists?(team_id: team.id, user_id: participants[rand_num].user_id)

if_condition_1 = (participants_hash[participants[rand_num].id] < student_review_num)
if_condition_2 = (!selected_participants.include? participants[rand_num].id)
if if_condition_1 and if_condition_2
# selected_participants cannot include duplicate num
selected_participants << participants[rand_num].id
participants_hash[participants[rand_num].id] += 1
end
# remove students who have already been assigned enough num of reviews out of participants array
participants.each do |participant|
if participants_hash[participant.id] == student_review_num
participants.delete_at(rand_num)
num_participants -= 1
end
end
end
else
#review num for last team can be different from other teams.
#prohibit one student to review his/her own artifact and selected_participants cannot include duplicate num
participants.each do |participant|
# avoid last team receives too many peer reviews
if !TeamsUser.exists?(team_id: team.id, user_id: participant.user_id) and selected_participants.size < num_reviews_per_team
selected_participants << participant.id
participants_hash[participant.id] += 1
end
end
end

begin
selected_participants.each {|index| ReviewResponseMap.where(:reviewee_id => team.id, :reviewer_id => index, :reviewed_object_id => assignment_id).first_or_create}
rescue
flash[:error] = "Automatic assignment of reviewer failed."
end
iterator += 1
end
end
</pre>

The method is made private so that it can only be called with in the controller and cannot directly be called through a view.

The complexity of the original method reduced after breaking it and can be easily readable now.

<pre>
def automatic_review_mapping_strategy(assignment_id, participants, teams, student_review_num=0, submission_review_num=0)
participants_hash = {}
participants.each { |participant| participants_hash[participant.id] = 0 }
#calculate reviewers for each team
num_participants = participants.size
if student_review_num != 0 and submission_review_num == 0
num_reviews_per_team = (participants.size * student_review_num * 1.0 / teams.size).round
exact_num_of_review_needed = participants.size * student_review_num
elsif student_review_num == 0 and submission_review_num != 0
num_reviews_per_team = submission_review_num
student_review_num = (teams.size * submission_review_num * 1.0 / participants.size).round
exact_num_of_review_needed = teams.size * submission_review_num
end
#Exception detection: If instructor want to assign too many reviews done by each student, there will be an error msg.
if student_review_num >= teams.size
flash[:error] = 'You cannot set the number of reviews done by each student to be greater than or equal to total number of teams [or "participants" if it is an individual assignment].'
end

peer_review_strategy(teams, num_participants, student_review_num, participants, participants_hash)

# after assigning peer reviews for each team, if there are still some peer reviewers not obtain enough peer review, just assign them to valid teams
if ReviewResponseMap.where(["reviewed_object_id = ? and created_at > ? and calibrate_to = ?", assignment_id, @@time_create_last_review_mapping_record, 0]).size < exact_num_of_review_needed
participants_with_insufficient_review_num = Array.new
participants_hash.each do |participant_id, review_num|
participants_with_insufficient_review_num << participant_id if review_num < student_review_num
end
unsorted_teams_hash = {}
ReviewResponseMap.where(["reviewed_object_id = ? and calibrate_to = ?", assignment_id, 0]).each do |response_map|
unless unsorted_teams_hash.has_key? (response_map.reviewee_id)
unsorted_teams_hash[response_map.reviewee_id] = 1
else
unsorted_teams_hash[response_map.reviewee_id] += 1
end
end
teams_hash = unsorted_teams_hash.sort_by{|_, v| v}.to_h
participants_with_insufficient_review_num.each do |participant_id|
teams_hash.each do |team_id, num_review_received|
unless TeamsUser.exists?(team_id: team_id, user_id: Participant.find(participant_id).user_id)
ReviewResponseMap.where(:reviewee_id => team_id, :reviewer_id => participant_id, :reviewed_object_id => assignment_id).first_or_create
teams_hash[team_id] += 1
teams_hash = teams_hash.sort_by{|_, v| v}.to_h
break
end
end
end
end
@@time_create_last_review_mapping_record = ReviewResponseMap.where(reviewed_object_id: assignment_id).last.created_at
end
</pre>

'''4. Moving code specific to models to models instead of controller'''

The method response_report contains code which generates reports based on the input of one of the three of 'ReviewResponseMap', 'FeedbackResponseMap', 'TeammateReviewResponseMap' and 'Calibration'. Calibration is a special case and should be handled in the controller itself. But the other three are models that are subclasses of ResponseMap model. The report is generated for each of the three by calling the ResponseMap model and obtaining the values by querying the database. Moving the code to the models and calling the methods in the model through the controller makes more sense than writing the code in controller.

The following is the code snippet from the original method which contains the calls to ResponseMap model:

<pre>
case @type
when "ReviewResponseMap"
if params[:user].nil?
# This is not a search, so find all reviewers for this assignment
response_maps_with_distinct_participant_id = ResponseMap.select("DISTINCT reviewer_id").where(["reviewed_object_id = ? and type = ? and calibrate_to = ?", @id, @type, 0])
@reviewers = []
response_maps_with_distinct_participant_id.each do |reviewer_id_from_response_map|
@reviewers << (AssignmentParticipant.find(reviewer_id_from_response_map.reviewer_id))
end
@reviewers = Participant.sort_by_name(@reviewers)
else
# This is a search, so find reviewers by user's full name
user = User.select("DISTINCT id").where(["fullname LIKE ?", '%'+params[:user][:fullname]+'%'])
@reviewers = AssignmentParticipant.where(["user_id IN (?) and parent_id = ?", user, @assignment.id])
end
# @review_scores[reveiwer_id][reviewee_id] = score for assignments not using vary_rubric_by_rounds feature
# @review_scores[reviewer_id][round][reviewee_id] = score for assignments using vary_rubric_by_rounds feature
@review_scores = @assignment.compute_reviews_hash
@avg_and_ranges= @assignment.compute_avg_and_ranges_hash
when "FeedbackResponseMap"
#Example query
#SELECT distinct reviewer_id FROM response_maps where type = 'FeedbackResponseMap' and
#reviewed_object_id in (select id from responses where
#map_id in (select id from response_maps where reviewed_object_id = 722 and type = 'ReviewResponseMap'))
@review_response_map_ids = ResponseMap.select("id").where(["reviewed_object_id = ? and type = ?", @id, 'ReviewResponseMap'])
@response_ids = Response.select("id").where(["map_id IN (?)", @review_response_map_ids])
@reviewers = ResponseMap.select("DISTINCT reviewer_id").where(["reviewed_object_id IN (?) and type = ?", @response_ids, @type])
when "TeammateReviewResponseMap"
#Example query
#SELECT distinct reviewer_id FROM response_maps where type = 'TeammateReviewResponseMap' and reviewed_object_id = 711
@reviewers = ResponseMap.select("DISTINCT reviewer_id").where(["reviewed_object_id = ? and type = ?", @id, 'TeammateReviewResponseMap'])
end
end
</pre>

The same code after moving the methods to their respective models looks as follows:

<pre>
case @type
when "ReviewResponseMap"
@review_user= params[:user]
#If review response is required call review_response_report method in review_response_map model
@reviewers = ReviewResponseMap.review_response_report(@id, @assignment,@type, @review_user)
@review_scores = @assignment.compute_reviews_hash
@avg_and_ranges= @assignment.compute_avg_and_ranges_hash
when "FeedbackResponseMap"
#If review report for feedback is required call feedback_response_report method in feedback_review_response_map model
@reviewers = FeedbackResponseMap.feedback_response_report(@id, @type)
when "TeammateReviewResponseMap"
#If review report for teammate is required call teammate_response_report method in teammate_review_response_map model
@reviewers = TeammateReviewResponseMap.teammate_response_report(@id)
end
end
</pre>

==References==

#[https://github.com/expertiza/expertiza Expertiza on GitHub]
#[https://github.com/harsha1007/expertiza Forked repository for the project]
#[http://expertiza.ncsu.edu/ Expertiza Main Page]

CSC/ECE 517 Spring 2016/Refactor review mapping controller.rb

2016-03-24T03:36:50Z

Ndhanir: /* 1. Unused variables and arguments */

==E1615. Refactoring the Review Mapping Controller==

This page provides details about the OSS project which was based on refactoring one of controllers related to peer reviewing strategies used in Expertiza.

__TOC__

=='''About Review mapping controller'''==

Review mapping controller contains methods related to peer reviewing strategies. It contains methods to add a reviewer, delete a reviewer, selecting a reviewer. Depending on the number of students and number of submissions, the topics to be reviewed are assigned to the students automatically. If a user wants to look for the team for a submission , it returns the team by comparing the submission id's with the team id's. Also, it assigns quizzes dynamically. Generation of review report, feedback report and teammate review is done.

=='''Code Improvements'''==

==='''1. Unused variables and arguments'''===

There are unused variables in the methods which use the stack unnecessarily. So, it is better to remove the unused variables or at the least indicate that a variable is unused.

For suppose when both keys and values are not used in a hash but are given as arguments, then the unused variables can be indicated by adding a "_" infront of the name or replace the unused variable with "_" to represent it as unused variable but allow them in arguments.

<pre>
Previous Code: teams_hash = unsorted_teams_hash.sort_by{|k, v| v}.to_h
</pre>
<pre>
After Changing the code: teams_hash = unsorted_teams_hash.sort_by{|_, v| v}.to_h
</pre>

In the above case teams_hash should consist of a hash with both keys and values but the sorting is done based on values. So the key is replaced with a "_" so that the user may deem it unused in the implementation of the process.

==='''2. Use sample instead of shuffle'''===

When sample is used, the elements in an array are chosen by using random and unique indices in the array so that the elements doesn't repeat in the array. This cannot be guaranteed in shuffle. Also by using shuffle[0] we are shuffling all the elements in the array and then picking the first element instead of picking a single element randomly which is more efficient. The following are the couple of places where shuffle[0] was used and is replaced by sample.

<pre>
Previous Code:

assignment_team = assignment_teams.to_a.shuffle[0] rescue nil

topic = assignment.candidate_topics_to_review(reviewer).to_a.shuffle[0] rescue nil
</pre>
<pre>
After Changing the code:

assignment_team = assignment_teams.to_a.sample rescue nil

topic = assignment.candidate_topics_to_review(reviewer).to_a.sample rescue nil
</pre>

==='''3. Cyclomatic complexity of automatic_review_mapping_strategy method'''===

The method automatic_review_mapping_strategy handles the number of reviews assigned to a individual and also the number of reviews that can be done with in a team. The method is very long and has many nested if statements due to which the complexity of the method is very high. Instead of a single method handling all the parts of the strategy, it is divided into several parts due to which the code is more readable and also the complexity of code is shared by each method.

The method first checks the number of participants that are in an assignment and the number of teams that are present. It then sets the values for the maximum number of reviews that are possible and also the minimum number that are required. Then it assigns the reviews to each of the teams randomly when a request for review is made by a participant. At last it checks if the participant has the minimum number of reviews required after allotting the reviews. If not, it assigns more reviews to valid teams so that the minimum requirement is met.

The part of the code that is moved out of automatic_review_mapping_strategy as peer_review_strategy:

<pre>
private
def peer_review_strategy(teams, num_participants, student_review_num, participants, participants_hash)
iterator = 0
teams.each do |team|
selected_participants = Array.new
if !team.equal? teams.last
#need to even out the # of reviews for teams
while selected_participants.size < num_reviews_per_team
num_participants_this_team = TeamsUser.where(team_id: team.id).size
#If there are some submitters or reviewers in this team, they are not treated as normal participants.
#They should be removed from 'num_participants_this_team'
TeamsUser.where(team_id: team.id).each do |team_user|
temp_participant = Participant.where(user_id: team_user.user_id, parent_id: assignment_id).first
num_participants_this_team -= 1 if temp_participant.can_review == false or temp_participant.can_submit == false
end
#if all outstanding participants are already in selected_participants, just break the loop.
break if selected_participants.size == participants.size - num_participants_this_team

# generate random number
if iterator == 0
rand_num = rand(0..num_participants-1)
else
min_value = participants_hash.values.min
#get the temp array including indices of participants, each participant has minimum review number in hash table.
participants_with_min_assigned_reviews = Array.new
participants.each do |participant|
participants_with_min_assigned_reviews << participants.index(participant) if participants_hash[participant.id] == min_value
end
#if participants_with_min_assigned_reviews is blank
if_condition_1 = participants_with_min_assigned_reviews.empty?
#or only one element in participants_with_min_assigned_reviews, prohibit one student to review his/her own artifact
if_condition_2 = (participants_with_min_assigned_reviews.size == 1 and TeamsUser.exists?(team_id: team.id, user_id: participants[participants_with_min_assigned_reviews[0]].user_id))
if if_condition_1 or if_condition_2
#use original method to get random number
rand_num = rand(0..num_participants-1)
else
#rand_num should be the position of this participant in original array
rand_num = participants_with_min_assigned_reviews[rand(0..participants_with_min_assigned_reviews.size-1)]
end
end
# prohibit one student to review his/her own artifact
next if TeamsUser.exists?(team_id: team.id, user_id: participants[rand_num].user_id)

if_condition_1 = (participants_hash[participants[rand_num].id] < student_review_num)
if_condition_2 = (!selected_participants.include? participants[rand_num].id)
if if_condition_1 and if_condition_2
# selected_participants cannot include duplicate num
selected_participants << participants[rand_num].id
participants_hash[participants[rand_num].id] += 1
end
# remove students who have already been assigned enough num of reviews out of participants array
participants.each do |participant|
if participants_hash[participant.id] == student_review_num
participants.delete_at(rand_num)
num_participants -= 1
end
end
end
else
#review num for last team can be different from other teams.
#prohibit one student to review his/her own artifact and selected_participants cannot include duplicate num
participants.each do |participant|
# avoid last team receives too many peer reviews
if !TeamsUser.exists?(team_id: team.id, user_id: participant.user_id) and selected_participants.size < num_reviews_per_team
selected_participants << participant.id
participants_hash[participant.id] += 1
end
end
end

begin
selected_participants.each {|index| ReviewResponseMap.where(:reviewee_id => team.id, :reviewer_id => index, :reviewed_object_id => assignment_id).first_or_create}
rescue
flash[:error] = "Automatic assignment of reviewer failed."
end
iterator += 1
end
end
</pre>

The method is made private so that it can only be called with in the controller and cannot directly be called through a view.

The complexity of the original method reduced after breaking it and can be easily readable now.

<pre>
def automatic_review_mapping_strategy(assignment_id, participants, teams, student_review_num=0, submission_review_num=0)
participants_hash = {}
participants.each { |participant| participants_hash[participant.id] = 0 }
#calculate reviewers for each team
num_participants = participants.size
if student_review_num != 0 and submission_review_num == 0
num_reviews_per_team = (participants.size * student_review_num * 1.0 / teams.size).round
exact_num_of_review_needed = participants.size * student_review_num
elsif student_review_num == 0 and submission_review_num != 0
num_reviews_per_team = submission_review_num
student_review_num = (teams.size * submission_review_num * 1.0 / participants.size).round
exact_num_of_review_needed = teams.size * submission_review_num
end
#Exception detection: If instructor want to assign too many reviews done by each student, there will be an error msg.
if student_review_num >= teams.size
flash[:error] = 'You cannot set the number of reviews done by each student to be greater than or equal to total number of teams [or "participants" if it is an individual assignment].'
end

peer_review_strategy(teams, num_participants, student_review_num, participants, participants_hash)

# after assigning peer reviews for each team, if there are still some peer reviewers not obtain enough peer review, just assign them to valid teams
if ReviewResponseMap.where(["reviewed_object_id = ? and created_at > ? and calibrate_to = ?", assignment_id, @@time_create_last_review_mapping_record, 0]).size < exact_num_of_review_needed
participants_with_insufficient_review_num = Array.new
participants_hash.each do |participant_id, review_num|
participants_with_insufficient_review_num << participant_id if review_num < student_review_num
end
unsorted_teams_hash = {}
ReviewResponseMap.where(["reviewed_object_id = ? and calibrate_to = ?", assignment_id, 0]).each do |response_map|
unless unsorted_teams_hash.has_key? (response_map.reviewee_id)
unsorted_teams_hash[response_map.reviewee_id] = 1
else
unsorted_teams_hash[response_map.reviewee_id] += 1
end
end
teams_hash = unsorted_teams_hash.sort_by{|_, v| v}.to_h
participants_with_insufficient_review_num.each do |participant_id|
teams_hash.each do |team_id, num_review_received|
unless TeamsUser.exists?(team_id: team_id, user_id: Participant.find(participant_id).user_id)
ReviewResponseMap.where(:reviewee_id => team_id, :reviewer_id => participant_id, :reviewed_object_id => assignment_id).first_or_create
teams_hash[team_id] += 1
teams_hash = teams_hash.sort_by{|_, v| v}.to_h
break
end
end
end
end
@@time_create_last_review_mapping_record = ReviewResponseMap.where(reviewed_object_id: assignment_id).last.created_at
end
</pre>

'''4. Moving code specific to models to models instead of controller'''

The method response_report contains code which generates reports based on the input of one of the three of 'ReviewResponseMap', 'FeedbackResponseMap', 'TeammateReviewResponseMap' and 'Calibration'. Calibration is a special case and should be handled in the controller itself. But the other three are models that are subclasses of ResponseMap model. The report is generated for each of the three by calling the ResponseMap model and obtaining the values by querying the database. Moving the code to the models and calling the methods in the model through the controller makes more sense than writing the code in controller.

The following is the code snippet from the original method which contains the calls to ResponseMap model:

<pre>
case @type
when "ReviewResponseMap"
if params[:user].nil?
# This is not a search, so find all reviewers for this assignment
response_maps_with_distinct_participant_id = ResponseMap.select("DISTINCT reviewer_id").where(["reviewed_object_id = ? and type = ? and calibrate_to = ?", @id, @type, 0])
@reviewers = []
response_maps_with_distinct_participant_id.each do |reviewer_id_from_response_map|
@reviewers << (AssignmentParticipant.find(reviewer_id_from_response_map.reviewer_id))
end
@reviewers = Participant.sort_by_name(@reviewers)
else
# This is a search, so find reviewers by user's full name
user = User.select("DISTINCT id").where(["fullname LIKE ?", '%'+params[:user][:fullname]+'%'])
@reviewers = AssignmentParticipant.where(["user_id IN (?) and parent_id = ?", user, @assignment.id])
end
# @review_scores[reveiwer_id][reviewee_id] = score for assignments not using vary_rubric_by_rounds feature
# @review_scores[reviewer_id][round][reviewee_id] = score for assignments using vary_rubric_by_rounds feature
@review_scores = @assignment.compute_reviews_hash
@avg_and_ranges= @assignment.compute_avg_and_ranges_hash
when "FeedbackResponseMap"
#Example query
#SELECT distinct reviewer_id FROM response_maps where type = 'FeedbackResponseMap' and
#reviewed_object_id in (select id from responses where
#map_id in (select id from response_maps where reviewed_object_id = 722 and type = 'ReviewResponseMap'))
@review_response_map_ids = ResponseMap.select("id").where(["reviewed_object_id = ? and type = ?", @id, 'ReviewResponseMap'])
@response_ids = Response.select("id").where(["map_id IN (?)", @review_response_map_ids])
@reviewers = ResponseMap.select("DISTINCT reviewer_id").where(["reviewed_object_id IN (?) and type = ?", @response_ids, @type])
when "TeammateReviewResponseMap"
#Example query
#SELECT distinct reviewer_id FROM response_maps where type = 'TeammateReviewResponseMap' and reviewed_object_id = 711
@reviewers = ResponseMap.select("DISTINCT reviewer_id").where(["reviewed_object_id = ? and type = ?", @id, 'TeammateReviewResponseMap'])
end
end
</pre>

The same code after moving the methods to their respective models looks as follows:

<pre>
case @type
when "ReviewResponseMap"
@review_user= params[:user]
#If review response is required call review_response_report method in review_response_map model
@reviewers = ReviewResponseMap.review_response_report(@id, @assignment,@type, @review_user)
@review_scores = @assignment.compute_reviews_hash
@avg_and_ranges= @assignment.compute_avg_and_ranges_hash
when "FeedbackResponseMap"
#If review report for feedback is required call feedback_response_report method in feedback_review_response_map model
@reviewers = FeedbackResponseMap.feedback_response_report(@id, @type)
when "TeammateReviewResponseMap"
#If review report for teammate is required call teammate_response_report method in teammate_review_response_map model
@reviewers = TeammateReviewResponseMap.teammate_response_report(@id)
end
end
</pre>

==References==

#[https://github.com/expertiza/expertiza Expertiza on GitHub]
#[https://github.com/harsha1007/expertiza Forked repository for the project]
#[http://expertiza.ncsu.edu/ Expertiza Main Page]

CSC/ECE 517 Spring 2016/Refactor review mapping controller.rb

2016-03-24T03:35:46Z

Ndhanir: /* References */

==E1615. Refactoring the Review Mapping Controller==

This page provides details about the OSS project which was based on refactoring one of controllers related to peer reviewing strategies used in Expertiza.

__TOC__

=='''About Review mapping controller'''==

Review mapping controller contains methods related to peer reviewing strategies. It contains methods to add a reviewer, delete a reviewer, selecting a reviewer. Depending on the number of students and number of submissions, the topics to be reviewed are assigned to the students automatically. If a user wants to look for the team for a submission , it returns the team by comparing the submission id's with the team id's. Also, it assigns quizzes dynamically. Generation of review report, feedback report and teammate review is done.

=='''Code Improvements'''==

==='''1. Unused variables and arguments'''===

There are unused variables in the methods which use the stack unnecessarily. So, it is better to remove the unused variables or at the least indicate that a variable is unused.

For suppose when both keys and values are not used in a hash but are given as arguments, then the unused variables can be indicated by adding a "_" infront of the name or replaced with "_" to represent it as unused variable but allow them arguments.

<pre>
Previous Code: teams_hash = unsorted_teams_hash.sort_by{|k, v| v}.to_h
</pre>
<pre>
After Changing the code: teams_hash = unsorted_teams_hash.sort_by{|_, v| v}.to_h
</pre>

In the above case teams_hash should consist of a hash with both keys and values but the sorting is done based on values. So the key is replaced with a "_" so that the user may deem it unused in the implementation of the process.

==='''2. Use sample instead of shuffle'''===

When sample is used, the elements in an array are chosen by using random and unique indices in the array so that the elements doesn't repeat in the array. This cannot be guaranteed in shuffle. Also by using shuffle[0] we are shuffling all the elements in the array and then picking the first element instead of picking a single element randomly which is more efficient. The following are the couple of places where shuffle[0] was used and is replaced by sample.

<pre>
Previous Code:

assignment_team = assignment_teams.to_a.shuffle[0] rescue nil

topic = assignment.candidate_topics_to_review(reviewer).to_a.shuffle[0] rescue nil
</pre>
<pre>
After Changing the code:

assignment_team = assignment_teams.to_a.sample rescue nil

topic = assignment.candidate_topics_to_review(reviewer).to_a.sample rescue nil
</pre>

==='''3. Cyclomatic complexity of automatic_review_mapping_strategy method'''===

The method automatic_review_mapping_strategy handles the number of reviews assigned to a individual and also the number of reviews that can be done with in a team. The method is very long and has many nested if statements due to which the complexity of the method is very high. Instead of a single method handling all the parts of the strategy, it is divided into several parts due to which the code is more readable and also the complexity of code is shared by each method.

The method first checks the number of participants that are in an assignment and the number of teams that are present. It then sets the values for the maximum number of reviews that are possible and also the minimum number that are required. Then it assigns the reviews to each of the teams randomly when a request for review is made by a participant. At last it checks if the participant has the minimum number of reviews required after allotting the reviews. If not, it assigns more reviews to valid teams so that the minimum requirement is met.

The part of the code that is moved out of automatic_review_mapping_strategy as peer_review_strategy:

<pre>
private
def peer_review_strategy(teams, num_participants, student_review_num, participants, participants_hash)
iterator = 0
teams.each do |team|
selected_participants = Array.new
if !team.equal? teams.last
#need to even out the # of reviews for teams
while selected_participants.size < num_reviews_per_team
num_participants_this_team = TeamsUser.where(team_id: team.id).size
#If there are some submitters or reviewers in this team, they are not treated as normal participants.
#They should be removed from 'num_participants_this_team'
TeamsUser.where(team_id: team.id).each do |team_user|
temp_participant = Participant.where(user_id: team_user.user_id, parent_id: assignment_id).first
num_participants_this_team -= 1 if temp_participant.can_review == false or temp_participant.can_submit == false
end
#if all outstanding participants are already in selected_participants, just break the loop.
break if selected_participants.size == participants.size - num_participants_this_team

# generate random number
if iterator == 0
rand_num = rand(0..num_participants-1)
else
min_value = participants_hash.values.min
#get the temp array including indices of participants, each participant has minimum review number in hash table.
participants_with_min_assigned_reviews = Array.new
participants.each do |participant|
participants_with_min_assigned_reviews << participants.index(participant) if participants_hash[participant.id] == min_value
end
#if participants_with_min_assigned_reviews is blank
if_condition_1 = participants_with_min_assigned_reviews.empty?
#or only one element in participants_with_min_assigned_reviews, prohibit one student to review his/her own artifact
if_condition_2 = (participants_with_min_assigned_reviews.size == 1 and TeamsUser.exists?(team_id: team.id, user_id: participants[participants_with_min_assigned_reviews[0]].user_id))
if if_condition_1 or if_condition_2
#use original method to get random number
rand_num = rand(0..num_participants-1)
else
#rand_num should be the position of this participant in original array
rand_num = participants_with_min_assigned_reviews[rand(0..participants_with_min_assigned_reviews.size-1)]
end
end
# prohibit one student to review his/her own artifact
next if TeamsUser.exists?(team_id: team.id, user_id: participants[rand_num].user_id)

if_condition_1 = (participants_hash[participants[rand_num].id] < student_review_num)
if_condition_2 = (!selected_participants.include? participants[rand_num].id)
if if_condition_1 and if_condition_2
# selected_participants cannot include duplicate num
selected_participants << participants[rand_num].id
participants_hash[participants[rand_num].id] += 1
end
# remove students who have already been assigned enough num of reviews out of participants array
participants.each do |participant|
if participants_hash[participant.id] == student_review_num
participants.delete_at(rand_num)
num_participants -= 1
end
end
end
else
#review num for last team can be different from other teams.
#prohibit one student to review his/her own artifact and selected_participants cannot include duplicate num
participants.each do |participant|
# avoid last team receives too many peer reviews
if !TeamsUser.exists?(team_id: team.id, user_id: participant.user_id) and selected_participants.size < num_reviews_per_team
selected_participants << participant.id
participants_hash[participant.id] += 1
end
end
end

begin
selected_participants.each {|index| ReviewResponseMap.where(:reviewee_id => team.id, :reviewer_id => index, :reviewed_object_id => assignment_id).first_or_create}
rescue
flash[:error] = "Automatic assignment of reviewer failed."
end
iterator += 1
end
end
</pre>

The method is made private so that it can only be called with in the controller and cannot directly be called through a view.

The complexity of the original method reduced after breaking it and can be easily readable now.

<pre>
def automatic_review_mapping_strategy(assignment_id, participants, teams, student_review_num=0, submission_review_num=0)
participants_hash = {}
participants.each { |participant| participants_hash[participant.id] = 0 }
#calculate reviewers for each team
num_participants = participants.size
if student_review_num != 0 and submission_review_num == 0
num_reviews_per_team = (participants.size * student_review_num * 1.0 / teams.size).round
exact_num_of_review_needed = participants.size * student_review_num
elsif student_review_num == 0 and submission_review_num != 0
num_reviews_per_team = submission_review_num
student_review_num = (teams.size * submission_review_num * 1.0 / participants.size).round
exact_num_of_review_needed = teams.size * submission_review_num
end
#Exception detection: If instructor want to assign too many reviews done by each student, there will be an error msg.
if student_review_num >= teams.size
flash[:error] = 'You cannot set the number of reviews done by each student to be greater than or equal to total number of teams [or "participants" if it is an individual assignment].'
end

peer_review_strategy(teams, num_participants, student_review_num, participants, participants_hash)

# after assigning peer reviews for each team, if there are still some peer reviewers not obtain enough peer review, just assign them to valid teams
if ReviewResponseMap.where(["reviewed_object_id = ? and created_at > ? and calibrate_to = ?", assignment_id, @@time_create_last_review_mapping_record, 0]).size < exact_num_of_review_needed
participants_with_insufficient_review_num = Array.new
participants_hash.each do |participant_id, review_num|
participants_with_insufficient_review_num << participant_id if review_num < student_review_num
end
unsorted_teams_hash = {}
ReviewResponseMap.where(["reviewed_object_id = ? and calibrate_to = ?", assignment_id, 0]).each do |response_map|
unless unsorted_teams_hash.has_key? (response_map.reviewee_id)
unsorted_teams_hash[response_map.reviewee_id] = 1
else
unsorted_teams_hash[response_map.reviewee_id] += 1
end
end
teams_hash = unsorted_teams_hash.sort_by{|_, v| v}.to_h
participants_with_insufficient_review_num.each do |participant_id|
teams_hash.each do |team_id, num_review_received|
unless TeamsUser.exists?(team_id: team_id, user_id: Participant.find(participant_id).user_id)
ReviewResponseMap.where(:reviewee_id => team_id, :reviewer_id => participant_id, :reviewed_object_id => assignment_id).first_or_create
teams_hash[team_id] += 1
teams_hash = teams_hash.sort_by{|_, v| v}.to_h
break
end
end
end
end
@@time_create_last_review_mapping_record = ReviewResponseMap.where(reviewed_object_id: assignment_id).last.created_at
end
</pre>

'''4. Moving code specific to models to models instead of controller'''

The method response_report contains code which generates reports based on the input of one of the three of 'ReviewResponseMap', 'FeedbackResponseMap', 'TeammateReviewResponseMap' and 'Calibration'. Calibration is a special case and should be handled in the controller itself. But the other three are models that are subclasses of ResponseMap model. The report is generated for each of the three by calling the ResponseMap model and obtaining the values by querying the database. Moving the code to the models and calling the methods in the model through the controller makes more sense than writing the code in controller.

The following is the code snippet from the original method which contains the calls to ResponseMap model:

<pre>
case @type
when "ReviewResponseMap"
if params[:user].nil?
# This is not a search, so find all reviewers for this assignment
response_maps_with_distinct_participant_id = ResponseMap.select("DISTINCT reviewer_id").where(["reviewed_object_id = ? and type = ? and calibrate_to = ?", @id, @type, 0])
@reviewers = []
response_maps_with_distinct_participant_id.each do |reviewer_id_from_response_map|
@reviewers << (AssignmentParticipant.find(reviewer_id_from_response_map.reviewer_id))
end
@reviewers = Participant.sort_by_name(@reviewers)
else
# This is a search, so find reviewers by user's full name
user = User.select("DISTINCT id").where(["fullname LIKE ?", '%'+params[:user][:fullname]+'%'])
@reviewers = AssignmentParticipant.where(["user_id IN (?) and parent_id = ?", user, @assignment.id])
end
# @review_scores[reveiwer_id][reviewee_id] = score for assignments not using vary_rubric_by_rounds feature
# @review_scores[reviewer_id][round][reviewee_id] = score for assignments using vary_rubric_by_rounds feature
@review_scores = @assignment.compute_reviews_hash
@avg_and_ranges= @assignment.compute_avg_and_ranges_hash
when "FeedbackResponseMap"
#Example query
#SELECT distinct reviewer_id FROM response_maps where type = 'FeedbackResponseMap' and
#reviewed_object_id in (select id from responses where
#map_id in (select id from response_maps where reviewed_object_id = 722 and type = 'ReviewResponseMap'))
@review_response_map_ids = ResponseMap.select("id").where(["reviewed_object_id = ? and type = ?", @id, 'ReviewResponseMap'])
@response_ids = Response.select("id").where(["map_id IN (?)", @review_response_map_ids])
@reviewers = ResponseMap.select("DISTINCT reviewer_id").where(["reviewed_object_id IN (?) and type = ?", @response_ids, @type])
when "TeammateReviewResponseMap"
#Example query
#SELECT distinct reviewer_id FROM response_maps where type = 'TeammateReviewResponseMap' and reviewed_object_id = 711
@reviewers = ResponseMap.select("DISTINCT reviewer_id").where(["reviewed_object_id = ? and type = ?", @id, 'TeammateReviewResponseMap'])
end
end
</pre>

The same code after moving the methods to their respective models looks as follows:

<pre>
case @type
when "ReviewResponseMap"
@review_user= params[:user]
#If review response is required call review_response_report method in review_response_map model
@reviewers = ReviewResponseMap.review_response_report(@id, @assignment,@type, @review_user)
@review_scores = @assignment.compute_reviews_hash
@avg_and_ranges= @assignment.compute_avg_and_ranges_hash
when "FeedbackResponseMap"
#If review report for feedback is required call feedback_response_report method in feedback_review_response_map model
@reviewers = FeedbackResponseMap.feedback_response_report(@id, @type)
when "TeammateReviewResponseMap"
#If review report for teammate is required call teammate_response_report method in teammate_review_response_map model
@reviewers = TeammateReviewResponseMap.teammate_response_report(@id)
end
end
</pre>

==References==

#[https://github.com/expertiza/expertiza Expertiza on GitHub]
#[https://github.com/harsha1007/expertiza Forked repository for the project]
#[http://expertiza.ncsu.edu/ Expertiza Main Page]

CSC/ECE 517 Spring 2016/Refactor review mapping controller.rb

2016-03-24T03:35:05Z

Ndhanir: /* E1615. Refactoring the Review Mapping Controller */

==E1615. Refactoring the Review Mapping Controller==

This page provides details about the OSS project which was based on refactoring one of controllers related to peer reviewing strategies used in Expertiza.

__TOC__

=='''About Review mapping controller'''==

Review mapping controller contains methods related to peer reviewing strategies. It contains methods to add a reviewer, delete a reviewer, selecting a reviewer. Depending on the number of students and number of submissions, the topics to be reviewed are assigned to the students automatically. If a user wants to look for the team for a submission , it returns the team by comparing the submission id's with the team id's. Also, it assigns quizzes dynamically. Generation of review report, feedback report and teammate review is done.

=='''Code Improvements'''==

==='''1. Unused variables and arguments'''===

There are unused variables in the methods which use the stack unnecessarily. So, it is better to remove the unused variables or at the least indicate that a variable is unused.

For suppose when both keys and values are not used in a hash but are given as arguments, then the unused variables can be indicated by adding a "_" infront of the name or replaced with "_" to represent it as unused variable but allow them arguments.

<pre>
Previous Code: teams_hash = unsorted_teams_hash.sort_by{|k, v| v}.to_h
</pre>
<pre>
After Changing the code: teams_hash = unsorted_teams_hash.sort_by{|_, v| v}.to_h
</pre>

In the above case teams_hash should consist of a hash with both keys and values but the sorting is done based on values. So the key is replaced with a "_" so that the user may deem it unused in the implementation of the process.

==='''2. Use sample instead of shuffle'''===

When sample is used, the elements in an array are chosen by using random and unique indices in the array so that the elements doesn't repeat in the array. This cannot be guaranteed in shuffle. Also by using shuffle[0] we are shuffling all the elements in the array and then picking the first element instead of picking a single element randomly which is more efficient. The following are the couple of places where shuffle[0] was used and is replaced by sample.

<pre>
Previous Code:

assignment_team = assignment_teams.to_a.shuffle[0] rescue nil

topic = assignment.candidate_topics_to_review(reviewer).to_a.shuffle[0] rescue nil
</pre>
<pre>
After Changing the code:

assignment_team = assignment_teams.to_a.sample rescue nil

topic = assignment.candidate_topics_to_review(reviewer).to_a.sample rescue nil
</pre>

==='''3. Cyclomatic complexity of automatic_review_mapping_strategy method'''===

The method automatic_review_mapping_strategy handles the number of reviews assigned to a individual and also the number of reviews that can be done with in a team. The method is very long and has many nested if statements due to which the complexity of the method is very high. Instead of a single method handling all the parts of the strategy, it is divided into several parts due to which the code is more readable and also the complexity of code is shared by each method.

The method first checks the number of participants that are in an assignment and the number of teams that are present. It then sets the values for the maximum number of reviews that are possible and also the minimum number that are required. Then it assigns the reviews to each of the teams randomly when a request for review is made by a participant. At last it checks if the participant has the minimum number of reviews required after allotting the reviews. If not, it assigns more reviews to valid teams so that the minimum requirement is met.

The part of the code that is moved out of automatic_review_mapping_strategy as peer_review_strategy:

<pre>
private
def peer_review_strategy(teams, num_participants, student_review_num, participants, participants_hash)
iterator = 0
teams.each do |team|
selected_participants = Array.new
if !team.equal? teams.last
#need to even out the # of reviews for teams
while selected_participants.size < num_reviews_per_team
num_participants_this_team = TeamsUser.where(team_id: team.id).size
#If there are some submitters or reviewers in this team, they are not treated as normal participants.
#They should be removed from 'num_participants_this_team'
TeamsUser.where(team_id: team.id).each do |team_user|
temp_participant = Participant.where(user_id: team_user.user_id, parent_id: assignment_id).first
num_participants_this_team -= 1 if temp_participant.can_review == false or temp_participant.can_submit == false
end
#if all outstanding participants are already in selected_participants, just break the loop.
break if selected_participants.size == participants.size - num_participants_this_team

# generate random number
if iterator == 0
rand_num = rand(0..num_participants-1)
else
min_value = participants_hash.values.min
#get the temp array including indices of participants, each participant has minimum review number in hash table.
participants_with_min_assigned_reviews = Array.new
participants.each do |participant|
participants_with_min_assigned_reviews << participants.index(participant) if participants_hash[participant.id] == min_value
end
#if participants_with_min_assigned_reviews is blank
if_condition_1 = participants_with_min_assigned_reviews.empty?
#or only one element in participants_with_min_assigned_reviews, prohibit one student to review his/her own artifact
if_condition_2 = (participants_with_min_assigned_reviews.size == 1 and TeamsUser.exists?(team_id: team.id, user_id: participants[participants_with_min_assigned_reviews[0]].user_id))
if if_condition_1 or if_condition_2
#use original method to get random number
rand_num = rand(0..num_participants-1)
else
#rand_num should be the position of this participant in original array
rand_num = participants_with_min_assigned_reviews[rand(0..participants_with_min_assigned_reviews.size-1)]
end
end
# prohibit one student to review his/her own artifact
next if TeamsUser.exists?(team_id: team.id, user_id: participants[rand_num].user_id)

if_condition_1 = (participants_hash[participants[rand_num].id] < student_review_num)
if_condition_2 = (!selected_participants.include? participants[rand_num].id)
if if_condition_1 and if_condition_2
# selected_participants cannot include duplicate num
selected_participants << participants[rand_num].id
participants_hash[participants[rand_num].id] += 1
end
# remove students who have already been assigned enough num of reviews out of participants array
participants.each do |participant|
if participants_hash[participant.id] == student_review_num
participants.delete_at(rand_num)
num_participants -= 1
end
end
end
else
#review num for last team can be different from other teams.
#prohibit one student to review his/her own artifact and selected_participants cannot include duplicate num
participants.each do |participant|
# avoid last team receives too many peer reviews
if !TeamsUser.exists?(team_id: team.id, user_id: participant.user_id) and selected_participants.size < num_reviews_per_team
selected_participants << participant.id
participants_hash[participant.id] += 1
end
end
end

begin
selected_participants.each {|index| ReviewResponseMap.where(:reviewee_id => team.id, :reviewer_id => index, :reviewed_object_id => assignment_id).first_or_create}
rescue
flash[:error] = "Automatic assignment of reviewer failed."
end
iterator += 1
end
end
</pre>

The method is made private so that it can only be called with in the controller and cannot directly be called through a view.

The complexity of the original method reduced after breaking it and can be easily readable now.

<pre>
def automatic_review_mapping_strategy(assignment_id, participants, teams, student_review_num=0, submission_review_num=0)
participants_hash = {}
participants.each { |participant| participants_hash[participant.id] = 0 }
#calculate reviewers for each team
num_participants = participants.size
if student_review_num != 0 and submission_review_num == 0
num_reviews_per_team = (participants.size * student_review_num * 1.0 / teams.size).round
exact_num_of_review_needed = participants.size * student_review_num
elsif student_review_num == 0 and submission_review_num != 0
num_reviews_per_team = submission_review_num
student_review_num = (teams.size * submission_review_num * 1.0 / participants.size).round
exact_num_of_review_needed = teams.size * submission_review_num
end
#Exception detection: If instructor want to assign too many reviews done by each student, there will be an error msg.
if student_review_num >= teams.size
flash[:error] = 'You cannot set the number of reviews done by each student to be greater than or equal to total number of teams [or "participants" if it is an individual assignment].'
end

peer_review_strategy(teams, num_participants, student_review_num, participants, participants_hash)

# after assigning peer reviews for each team, if there are still some peer reviewers not obtain enough peer review, just assign them to valid teams
if ReviewResponseMap.where(["reviewed_object_id = ? and created_at > ? and calibrate_to = ?", assignment_id, @@time_create_last_review_mapping_record, 0]).size < exact_num_of_review_needed
participants_with_insufficient_review_num = Array.new
participants_hash.each do |participant_id, review_num|
participants_with_insufficient_review_num << participant_id if review_num < student_review_num
end
unsorted_teams_hash = {}
ReviewResponseMap.where(["reviewed_object_id = ? and calibrate_to = ?", assignment_id, 0]).each do |response_map|
unless unsorted_teams_hash.has_key? (response_map.reviewee_id)
unsorted_teams_hash[response_map.reviewee_id] = 1
else
unsorted_teams_hash[response_map.reviewee_id] += 1
end
end
teams_hash = unsorted_teams_hash.sort_by{|_, v| v}.to_h
participants_with_insufficient_review_num.each do |participant_id|
teams_hash.each do |team_id, num_review_received|
unless TeamsUser.exists?(team_id: team_id, user_id: Participant.find(participant_id).user_id)
ReviewResponseMap.where(:reviewee_id => team_id, :reviewer_id => participant_id, :reviewed_object_id => assignment_id).first_or_create
teams_hash[team_id] += 1
teams_hash = teams_hash.sort_by{|_, v| v}.to_h
break
end
end
end
end
@@time_create_last_review_mapping_record = ReviewResponseMap.where(reviewed_object_id: assignment_id).last.created_at
end
</pre>

'''4. Moving code specific to models to models instead of controller'''

The method response_report contains code which generates reports based on the input of one of the three of 'ReviewResponseMap', 'FeedbackResponseMap', 'TeammateReviewResponseMap' and 'Calibration'. Calibration is a special case and should be handled in the controller itself. But the other three are models that are subclasses of ResponseMap model. The report is generated for each of the three by calling the ResponseMap model and obtaining the values by querying the database. Moving the code to the models and calling the methods in the model through the controller makes more sense than writing the code in controller.

The following is the code snippet from the original method which contains the calls to ResponseMap model:

<pre>
case @type
when "ReviewResponseMap"
if params[:user].nil?
# This is not a search, so find all reviewers for this assignment
response_maps_with_distinct_participant_id = ResponseMap.select("DISTINCT reviewer_id").where(["reviewed_object_id = ? and type = ? and calibrate_to = ?", @id, @type, 0])
@reviewers = []
response_maps_with_distinct_participant_id.each do |reviewer_id_from_response_map|
@reviewers << (AssignmentParticipant.find(reviewer_id_from_response_map.reviewer_id))
end
@reviewers = Participant.sort_by_name(@reviewers)
else
# This is a search, so find reviewers by user's full name
user = User.select("DISTINCT id").where(["fullname LIKE ?", '%'+params[:user][:fullname]+'%'])
@reviewers = AssignmentParticipant.where(["user_id IN (?) and parent_id = ?", user, @assignment.id])
end
# @review_scores[reveiwer_id][reviewee_id] = score for assignments not using vary_rubric_by_rounds feature
# @review_scores[reviewer_id][round][reviewee_id] = score for assignments using vary_rubric_by_rounds feature
@review_scores = @assignment.compute_reviews_hash
@avg_and_ranges= @assignment.compute_avg_and_ranges_hash
when "FeedbackResponseMap"
#Example query
#SELECT distinct reviewer_id FROM response_maps where type = 'FeedbackResponseMap' and
#reviewed_object_id in (select id from responses where
#map_id in (select id from response_maps where reviewed_object_id = 722 and type = 'ReviewResponseMap'))
@review_response_map_ids = ResponseMap.select("id").where(["reviewed_object_id = ? and type = ?", @id, 'ReviewResponseMap'])
@response_ids = Response.select("id").where(["map_id IN (?)", @review_response_map_ids])
@reviewers = ResponseMap.select("DISTINCT reviewer_id").where(["reviewed_object_id IN (?) and type = ?", @response_ids, @type])
when "TeammateReviewResponseMap"
#Example query
#SELECT distinct reviewer_id FROM response_maps where type = 'TeammateReviewResponseMap' and reviewed_object_id = 711
@reviewers = ResponseMap.select("DISTINCT reviewer_id").where(["reviewed_object_id = ? and type = ?", @id, 'TeammateReviewResponseMap'])
end
end
</pre>

The same code after moving the methods to their respective models looks as follows:

<pre>
case @type
when "ReviewResponseMap"
@review_user= params[:user]
#If review response is required call review_response_report method in review_response_map model
@reviewers = ReviewResponseMap.review_response_report(@id, @assignment,@type, @review_user)
@review_scores = @assignment.compute_reviews_hash
@avg_and_ranges= @assignment.compute_avg_and_ranges_hash
when "FeedbackResponseMap"
#If review report for feedback is required call feedback_response_report method in feedback_review_response_map model
@reviewers = FeedbackResponseMap.feedback_response_report(@id, @type)
when "TeammateReviewResponseMap"
#If review report for teammate is required call teammate_response_report method in teammate_review_response_map model
@reviewers = TeammateReviewResponseMap.teammate_response_report(@id)
end
end
</pre>

===References===

#[https://github.com/expertiza/expertiza Expertiza on GitHub]
#[https://github.com/harsha1007/expertiza Forked repository for the project]
#[http://expertiza.ncsu.edu/ Expertiza Main Page]

2016-03-23T23:30:19Z

Ndhanir: /* Wiki write up */

CSC/ECE 517 Spring 2016/Refactor review mapping controller.rb

2016-03-23T22:25:54Z

Ndhanir:

==E1615. Refactoring the Review Mapping Controller==

This page provides details about the OSS project which was based on refactoring one of controllers related to peer reviewing strategies used in Expertiza.

__TOC__

===Introduction to Expertiza===

[http://expertiza.ncsu.edu/ Expertiza] is an open source project based on [http://rubyonrails.org/ Ruby on Rails] framework. Expertiza allows the instructor to create new assignments and customize new or existing assignments. It also allows the instructor to create a list of topics the students can sign up for. Students can form teams in Expertiza to work on various projects and assignments. Students can also peer review other students' submissions. Expertiza supports submission across various document types, including the URLs and wiki pages.

===Problem Statement===
The following tasks were accomplished in this project:

* Improved the clarity of code by improving the variable and parameter names.
* Long character strings were taken and given appropriate names.
* Handled pagination by a separate helper module, which can be used by multiple controllers.
* Implemented action_allowed for access_control to prevent unauthorized access of methods.
* Prevented displaying of all versions for all users and tables when a user views the index page.
* Added missing CRUD methods to Versions Controller
* Added RSPEC testcases for testing changes done in Versions Controller

===About Versions Controller===
This class manages different versions of reviews. If a reviewer reviews a submission, and after that, the author revises the submission, the next time the reviewer does a review (s)he will create a new version. Sometimes it’s necessary to find the current version of a review; sometimes it’s necessary to find all versions. Similarly, a user may want to delete the current version of a review, or all versions of a review.
Pagination of versions helps the user to view a subset of versions at a time. Considering the huge number of versions in the system, it is very useful to have a pagination mechanism and a filtering mechanism which can be applied on the whole set of versions. The idea is to display the versions in an ordered, comprehensible and logical manner. In Expertiza the gem ‘will_paginate’ is used to achieve pagination.

===Current Implementation===

=====Functionality=====
* Any user irrespective of his/ her privileges can view all the versions.
::The versions which a particular user can view should be restricted based on the privileges of the user. For instance, only a user with Administrator privileges should be able to view all the versions in the system. However, that is not the case now. Every user can view all the versions irrespective of whether the user is a student or an administrator.
* Any user can delete any version
::The versions which a particular user can delete should be restricted based on the privileges of the user. For instance, a student should not be allowed to delete any version. According to the current implementation any user can delete any version in the system.
* Filtering of versions were restricted to the current user
::The filtering options on versions were restricted to the current user. Sometimes a user might want to view versions associated with other users. For instance, an instructor might want to view the list of versions created by a particular student. This is not possible with the current implementation.

=====Drawbacks and Solutions=====
* '''Problem 1''': The method paginate_list is doing more than one thing.
::The method paginate_list was building a complex search criteria based on the input params, getting the list of versions from the Database matching this search criteria and then calling the Page API. All these tasks in a single method made it difficult to understand.
<pre>
# For filtering the versions list with proper search and pagination.
def paginate_list(id, user_id, item_type, event, datetime)
# Set up the search criteria
criteria = ''
criteria = criteria + "id = #{id} AND " if id && id.to_i > 0
if current_user_role? == 'Super-Administrator'
criteria = criteria + "whodunnit = #{user_id} AND " if user_id && user_id.to_i > 0
end
criteria = criteria + "whodunnit = #{current_user.try(:id)} AND " if current_user.try(:id) && current_user.try(:id).to_i > 0
criteria = criteria + "item_type = '#{item_type}' AND " if item_type && !(item_type.eql? 'Any')
criteria = criteria + "event = '#{event}' AND " if event && !(event.eql? 'Any')
criteria = criteria + "created_at >= '#{time_to_string(params[:start_time])}' AND "
criteria = criteria + "created_at <= '#{time_to_string(params[:end_time])}' AND "

if current_role == 'Instructor' || current_role == 'Administrator'

end

# Remove the last ' AND '
criteria = criteria[0..-5]

versions = Version.page(params[:page]).order('id').per_page(25).where(criteria)
versions
end
</pre>
* '''Solution''': The implementation has been changed in such a way that the versions which a user is allowed to see depends on the privileges of the user. The approach we have taken is as follows:
**An administrator can see all the versions
**An instructor can see all the versions created by him and other users who are in his course or are participants in the assignments he creates.
**A TA can see all the versions created by him and other users who are in the course for which he/ she assists.
**A Student can see all the versions created by him/ her.
* '''Problem 2''': The search criteria created in the method paginate_list was difficult to comprehend.
::The code which builds the search criteria in the method paginate_list uses many string literals and conditions and is hardly intuitive. The programmer will have to spend some time to understand what the code is really doing.
* '''Solution''': The implementation has been changed. A student is not allowed to delete any versions now. Other types of users, for instance administrators, instructors and TAs are allowed to delete only the versions they are authorized to view.
* '''Problem 3''': The paginate method can be moved to a helper class.
::VersionsController is not the only component which require to paginate items. There are other components too. For instance, the UsersController has to paginate the list of users. Hence the Paginate method can be moved to a helper class which can be accessed by other components as well.
* '''Solution''': The filtering options has also been enhanced. The current user can now choose as part of the version search filter any user from a list of users if the current user is authorized to see the versions created by that user.

===New Implementation===
*The method paginate_list has been split into 2 methods now.
** BuildSearchCriteria – as the name suggests the sole purpose of this method is to build a search criteria based on the input search filters when the current user initiates a search in versions.
** paginate_list – this method will call the paginate API.
:First the search criteria is built, then the criteria is applied to versions in the database to get all versions which matches the criteria and then the retrieved versions are paginated.
<pre>
# pagination.
def paginate_list(versions)
paginate(versions, VERSIONS_PER_PAGE);
end

def BuildSearchCriteria(id, user_id, item_type, event)
# Set up the search criteria
search_criteria = ''
search_criteria = search_criteria + add_id_filter_if_valid(id).to_s
if current_user_role? == 'Super-Administrator'
search_criteria = search_criteria + add_user_filter_for_super_admin(user_id).to_s
end
search_criteria = search_criteria + add_user_filter
search_criteria = search_criteria + add_version_type_filter(item_type).to_s
search_criteria = search_criteria + add_event_filter(event).to_s
search_criteria = search_criteria + add_date_time_filter
search_criteria
end
</pre>
* The string literals and conditions in the method paginate_list were replaced with methods with intuitive names so that the programmer can understand the code more easily. We also removed an empty if clause and a redundant statement.
<pre>
def add_id_filter_if_valid (id)
"id = #{id} AND " if id && id.to_i > 0
end

def add_user_filter_for_super_admin (user_id)
"whodunnit = #{user_id} AND " if user_id && user_id.to_i > 0
end

def add_user_filter
"whodunnit = #{current_user.try(:id)} AND " if current_user.try(:id) && current_user.try(:id).to_i > 0
end

def add_event_filter (event)
"event = '#{event}' AND " if event && !(event.eql? 'Any')
end

def add_date_time_filter
"created_at >= '#{time_to_string(params[:start_time])}' AND " +
"created_at <= '#{time_to_string(params[:end_time])}'"
end

def add_version_type_filter (version_type)
"item_type = '#{version_type}' AND " if version_type && !(version_type.eql? 'Any')
end
</pre>
* The paginate method has been moved to the helper class Pagination_Helper. This new method can be now reused by the different components like UsersController etc. The method receives two parameters, first the list to paginate and second the number of items to be displayed in a page.

<pre>
module PaginationHelper

def paginate (items, number_of_items_per_page)
items.page(params[:page]).per_page(number_of_items_per_page)
end

end
</pre>

===Code improvements===
* Introduced a constant VERSIONS_PER_PAGE and assigned the value 25 to it. The pagination algorithm for VersionsController displays at most 25 versions in a page. The existing implementation uses the value 25 straight in the code and there are few problems associated with such an approach.
** It is not easy to understand what 25 is unless the programmer takes a close look at the code.
** In case if the value 25 is used at more than one places and in future a new requirement comes to show at most 30 versions in a page, all the values will have to be modified. It is not very DRY.
* The VersionsController was overriding AccessHelper - action_allowed? method to return true in all the cases. This was violating the whole purpose of the method action_allowed?. The purpose of this method is to determine whether the user who is triggering a CRUD operation is allowed to do so. So when the current user invokes a CRUD operation, the action_allowed? method is invoked first and if the method returns true the CRUD operation is triggered or else the user is intimated with a message and gracefully exited. Hence, when the action_allowed? method is overridden to return true always, it results in providing unauthorized access to certain users.

<pre>
def action_allowed?
true
end
</pre>

:With the new implementation the AccessHelper - action_allowed? method has been modified in such a way that unauthorized access is prevented. As per the new algorithm, 'new', 'create', 'edit', 'update' cannot be invoked by any user. These operations can be accessed only by ‘papertrail’ gem. Only an ‘Administrator’ or ‘Super-Administrator’ can call 'destroy_all' method. All the other methods are accessible to ‘Administrator’, ‘Super-Administrator’, ‘Instructor’, ‘Teaching Assistant’ and ‘Student’.

<pre>
def action_allowed?
case params[:action]
when 'new', 'create', 'edit', 'update'
#Modifications can only be done by papertrail
return false
when 'destroy_all'
['Super-Administrator',
'Administrator'].include? current_role_name
else
#Allow all others
['Super-Administrator',
'Administrator',
'Instructor',
'Teaching Assistant',
'Student'].include? current_role_name
end
end
</pre>

===Automated Testing using RSPEC===
The current version of expertiza did not have any test for VersionsController. Using the test driven development(TDD) approach, we have added an exhaustive set of RSPEC tests for VersionsController, to test all the modifications we have done to the code of the controller class. The tests use double and stub features of rspec-rails gem, to fake the log in by different users - Administrator, Instructor, Student etc. The tests can be executed "rpec spec" command as shown below.
<pre>
user-expertiza $rspec spec
.
.
.
Finished in 5.39 seconds (files took 25.33 seconds to load)
66 examples, 0 failures

Randomized with seed 19254
.
.
</pre>

===Testing from UI===
Following are a few testcases with respectto our code changes that can be tried from UI:
1. To go to versions index page, type in the following url after logging in:
http://152.46.16.81:3000/versions

2. After logging in as student/instructor or admin : Try accessing the new, create, edit, update actions. These actions are not allowed to any of the users.
http://152.46.16.81:3000/versions/new
This calls the new action. In the current production version of expertiza, it is unhandled and application gives a default 404 page.

3. Another feature that can be tested from UI is Pagination. Try searching for a user's versions and see if the results are paginated or not. Search here:
http://152.46.16.81:3000/versions/search

4. Visit the same URL as step 3, you should see only the students under that instructor in the users dropdown.

===References===

#[https://github.com/expertiza/expertiza Expertiza on GitHub]
#[https://github.com/WintersLt/expertiza GitHub Project Repository Fork]
#[http://expertiza.ncsu.edu/ The live Expertiza website]
#[http://bit.ly/myexpertiza Demo link]
#[http://wikis.lib.ncsu.edu/index.php/Expertiza Expertiza project documentation wiki]
#[https://relishapp.com/rspec Rspec Documentation]
#Clean Code: A handbook of agile software craftsmanship. Author: Robert C Martin

User:Ndhanir

2016-03-23T22:23:30Z

Ndhanir:

User:Ndhanir

2016-02-17T21:48:51Z

Ndhanir:

User:Yrathor

2016-02-16T01:08:46Z

Ndhanir: /* Databases */

'''Web.py Introduction'''

Web.py is a [https://en.wikipedia.org/wiki/Free_and_open_source free and open source] [https://en.wikipedia.org/wiki/Web_application_framework web application framework] that is as simple as it is powerful.

The web.py slogan is: "Think about the ideal way to write a web app. Write the code to make it happen.". The goal of web.py is to build the ideal way to make web apps. In web.py, Instead of exposing [https://en.wikipedia.org/wiki/Python_(programming_language) Python] objects, it allows you to build HTTP responses. Instead of trying to make the database look like an object, web.py makes the database easier to use. And instead of coming up with yet another way to write [https://en.wikipedia.org/wiki/HTML HTML], the web.py template system tries to bring Python into HTML.

Some of the sites which uses web.py are
* [http://frinki.com/ Frinki], a new social network in spanish.
* [http://www.oyster.com/ oyster.com], a website that reviews hotels uses web.py for the entire website.
* [http://makehistory.national911memorial.org/ Make History], a project of the 9/11 memorial museum.

=='''History'''==

Web.py was originally published while Aaron swartz worked at [http://reddit.com/ reddit.com], where the site used it as it grew to become one of the top 1000 sites according to Alexa and served millions of daily page views. "It's the anti-framework framework. web.py doesn't get in your way." explained founder Steve Huffman.

=='''Why Web.py?'''==

The reasons for using web.py are
* Simplicity
* Freedom
* writing clean code
* minimalism
* a solid web framework

=='''Installation'''==
To install web.py on Linux based operating system,
* Firstly, download the following tar file:
wget http://webpy.org/static/web.py-0.37.tar.gz
* Extract the downloaded tar file:
tar -zxvf web.py-0.37.tar.gz
* Go to web.py-0.37 directory:
cd web.py-0.37/
* Install and make it accessible to all the applications:
sudo python setup.py install

=='''Web.py skeleton'''==

Every web application needs a skeleton. A sample skeleton of web.py application looks as follows.

* doc: Documentation of all the files.
* licenses: All the licenses of the project and the libraries used in the application.
* requirements: Specifying the third party libraries.
* sh: bash script files of the project.
* www: The required web application itself.
** app: contains the application modules.
*** controllers: This module contains the handler modules of controller package.
*** Tools: Tools that are used for the project.
*** views: Template files.
*** models: Database models of the application.
*** bridge: It is used to communicate with the server which is written in another language.
** lib: The library files developed for the project. These are different from the tools mentioned in the app. Libraries can be used in other projects where as tools are limited to the project itself.
** public: This folder contains the minimized compiled CSS, Javascript, CoffeeScript files and images so the files in this folder are production ready and can't be used in development.
** static: Contains the development CSS, CoffeeScript, Javascript, and images files of the project.
** test: As you can guess easily, these are the test files.
** tmp: Garbage files.
** main.py: These are the only files that are directly executed by the server.
** main_development.py: Main executable file in development mode.
** settings.py: Global constants and settings of the application.
** urls.py: Contains URL's of the application

=='''Features of web.py'''==

''web.py has two unique features''

===Databases===

The database package lets you access various different databases. Accessing different databases refers to connecting multiple databases. However, its not an [https://en.wikipedia.org/wiki/Object-relational_mapping ORM]. It is similar to sqlite3 package which doesn't use ORM. This feature is missing in [https://en.wikipedia.org/wiki/Django_(web_framework) Django] (another web framework). web.py has flexible modules which allow the user to wipe it out completely and use with another web framework.
Before creating database object, the user must install appropriate database library like psycopg2 for [https://en.wikipedia.org/wiki/PostgreSQL PostgreSQL], MySQLdb for [https://en.wikipedia.org/wiki/MySQL MySQL] and sqlite3 for [https://en.wikipedia.org/wiki/SQLite SQLite]. Working with more databases is not at all difficult with web.py which is explained by the following example:
<pre>
db1 = web.database(dbn='postgres', db='dbname1', user='username1', pw='password2')
db2 = web.database(dbn='postgres', db='dbname2', user='username2', pw='password2')
</pre>

===Forms===

A forms package is present in web.py which let's us create forms and [https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/Forms/Data_form_validation validators]. The form module of web.py allows the ability to generate html forms, get user input, and validate it before processing it or adding it to a database. But it doesn't have built-in protection against [https://en.wikipedia.org/wiki/Cross-site_request_forgery CSRF]. A sample login form is as follows:
<pre>
login = form.Form(
form.Textbox('username'),
form.Password('password'),
form.Button('Login'),
)
</pre>

Another interesting feature about web.py is its flexibility. It has flexible modules which can be used with another framework.

=='''Hello world example'''==
<pre>
import web
urls = (
'/', 'index'
)

class index:
def GET(self):
return "Hello, ECE517!"

if __name__ == "__main__":
app = web.application(urls, globals())
app.run()
</pre>

If the above example is considered, then we start the application by importing the web.py module using the following command
import web

The most important part of the website is its URL structure. web.py makes it easy to make great URLs.

<pre>
urls = (
'/', 'index'
)
</pre>

The first part is a [https://en.wikipedia.org/wiki/Regular_expression regular expressions] that matches a URL, like /, /help/faq, /item/, etc. The parentheses say to capture that piece of the matched data for use later on. The second part is the name of a class to send the request to, like index, view, welcome, hello (which gets the hello ECE517 of the welcome module), or get_\1. \1 is replaced by the first capture of your regular expression; any remaining captures get passed to your function.

Web.py's URL handling scheme is simple yet powerful and flexible. At the top of each application, you usually see the full URL dispatching scheme defined as a tuple.

<pre>
urls = (
"/tasks/?", "signin",
"/tasks/list", "listing",
"/tasks/post", "post",
"/tasks/act", "actions",
"/tasks/signup", "signup"
)
</pre>

The format of this tuple is: url-path-pattern, handler-class this pattern will repeat as more url patterns are defined.

=='''Conclusion'''==

web.py is a minimalist framework whose aim is not to abstract away the details of interacting with the Web, but to make that interaction easier. It is designed in such a way that user will get started quickly with web.py and find writing HTTP GET function handlers directly. Likewise, the web.py database system does not abstract away SQL rather than hide the fact that you're querying a database. It hides the details of working with different databases.

=='''References'''==
[[#References|[1]]] web.py official website: http://webpy.org/

[[#References|[2]]] python development story: http://faruk.akgul.org/blog/python-development-story-why-webpy/

[[#References|[3]]] pillars of python-six web frameworks: http://www.infoworld.com/article/2622836/application-development/pillars-of-python--six-python-web-frameworks-compared.html?page=2

[[#References|[4]]] Django vs flash vs pyramid https://www.airpair.com/python/posts/django-flask-pyramid

[[#References|[5]]] Form Validation: https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/Forms/Data_form_validation

[[#References|[6]]] Aaron swartz about web.py http://www.aaronsw.com/weblog/rewritingreddit

[[#References|[7]]] https://www.wikipedia.org/

User:Ndhanir

2016-02-15T22:06:57Z

Ndhanir:

2016-02-13T05:58:14Z

Ndhanir: /* Databases */

{{Infobox software
| name =
| logo = 
| Author = [https://en.wikipedia.org/wiki/Aaron_Swartz Aaron swartz]
| released = 
| latest release version = web.py-0.37
| latest release date = 
| size = {{nowrap|88 [[kilobyte|KB]]}}
| status = Active
| programming language = Python
| Type = Web application Framework
| website = {{webpy.org}}
}}

Web.py is a [https://en.wikipedia.org/wiki/Free_and_open_source free and open source] [https://en.wikipedia.org/wiki/Web_framework Web application framework] that is as simple as it is powerful.

The web.py slogan is: "Think about the ideal way to write a web app. Write the code to make it happen."[http://webpy.org/]. The goal of web.py is to build the ideal way to make web apps. In web.py, Instead of exposing [[Python]] objects, it allows you to build [[HTTP]] responses. Instead of trying to make the [[database]] look like an object, web.py makes the database easier to use. And instead of coming up with yet another way to write [[HTML]], the web.py template system tries to bring Python into [[HTML]].

Some of the [https://en.wikipedia.org/wiki/Website websites] which uses web.py are
* [http://frinki.com/ Frinki], a new social network in spanish.
* [http://www.oyster.com/ oyster.com], a website that reviews hotels uses web.py for the entire website.
* [http://makehistory.national911memorial.org/ Make History], a project of the 9/11 memorial museum.

=='''History'''==

Web.py was originally published while Aaron swartz worked at [http://reddit.com/ reddit.com], where the site used it as it grew to become one of the top 1000 sites according to [http://www.alexa.com/topsites/global;1 Alexa] and served millions of daily page views. "It's the anti-framework framework. web.py doesn't get in your way." explained founder Steve Huffman.

=='''Python'''==

Python is a [https://en.wikipedia.org/wiki/Multi-paradigm_programming_language multi-paradigm programming language]: object-oriented programming and [https://en.wikipedia.org/wiki/Structured_programming structured programming] are fully supported, and there are a number of language features which support functional programming and aspect-oriented programming (including by [https://en.wikipedia.org/wiki/Metaprogramming metaprogramming]). Python uses [https://en.wikipedia.org/wiki/Dynamic_typing dynamic typing] and a combination of reference counting and a cycle-detecting garbage collector for [https://en.wikipedia.org/wiki/Memory_management memory management]. An important feature of Python is dynamic [https://en.wikipedia.org/wiki/Name_resolution_(programming_languages) name resolution], which binds method and variable names during program execution.

Ruby's creator, Yukihiro Matsumoto, has said: "I wanted a scripting language that was more powerful than Perl, and more object-oriented than [https://en.wikipedia.org/wiki/Python_(programming_language) '''Python''']. That's why I decided to design my own language."

The world of Python web frameworks is full of choices. Django, Flask, Pyramid, Tornado, Bottle, Diesel, Pecan, Falcon, web.py, web2py and many more are competing for developer mindshare. The developer needs to cut the options down to one framework depending on the type of application.

=='''Why Web.py?'''==

The reasons for using web.py are
* Simplicity
* Freedom
* Writing clean code
* Minimalism
* A solid web framework

=='''Installation'''==
To install web.py,
* Firstly, download the following tar file:
wget http://webpy.org/static/web.py-0.37.tar.gz
* Extract the downloaded tar file:
tar -zxvf web.py-0.37.tar.gz
* Go to web.py-0.37 directory:
cd web.py-0.37/
* Install and make it accessible to all the applications:
sudo python setup.py install

=='''Web.py skeleton'''==

Every web application needs a skeleton. A sample skeleton of web.py application looks as follows.

* doc: Documentation of all the files.
* licenses: All the licenses of the project and the libraries used in the application.
* requirements: Specifying the third party libraries.
* sh: bash script files of the project.
* www: The required web application itself.
** app: contains the application modules.
*** controllers: This module contains the handler modules of controller package.
*** Tools: Tools that are used for the project.
*** views: Template files.
*** models: Database models of the application.
*** bridge: It is used to communicate with the server which is written in another language.
** lib: The library files developed for the project. These are different from the tools mentioned in the app. Libraries can be used in other projects where as tools are limited to the project itself.
** public: This folder contains the minimized compiled CSS, Javascript, CoffeeScript files and images so the files in this folder are production ready and can't be used in development.
** static: Contains the development CSS, CoffeeScript, Javascript, and images files of the project.
** test: As you can guess easily, these are the test files.
** tmp: Garbage files.
** main.py: These are the only files that are directly executed by the server.
** main_development.py: Main executable file in development mode.
** settings.py: Global constants and settings of the application.
** urls.py: Contains URL's of the application

=='''Features of web.py'''==

''web.py has two interesting features''

===Databases===

The database package lets the user access different databases. Accessing different databases refers to connecting to multiple databases. However, its not an [https://en.wikipedia.org/wiki/Object-relational_mapping ORM].
The databases in ruby benefit the people who are good at SQL and don't like to use ORM. This feature is missing in [https://en.wikipedia.org/wiki/Django_(web_framework) Django] (another web framework based on python). [http://webpy.org/docs/0.3/tutorial]

===Forms===

A forms package is present in web.py which let's us create forms and [https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/Forms/Data_form_validation validators]. The form module of web.py allows the ability to generate html forms, get user input, and validate it before processing it or adding it to a database. But it doesn't have built-in protection against [https://en.wikipedia.org/wiki/Cross-site_request_forgery CSRF]. A basic login form would look as given below:
<pre>
login = form.Form(
form.Textbox('username'),
form.Password('password'),
form.Button('Login'),
)
</pre>

Another interesting feature about web.py is its flexibility. It has flexible modules which can be used with another framework.

=='''Hello world example'''==
<pre>
import web
urls = (
'/', 'index'
)

class index:
def GET(self):
return "Hello, ECE517!"

if __name__ == "__main__":
app = web.application(urls, globals())
app.run()
</pre>

Consider the given example, the user start the application by importing the web.py module using the following command
import web

The most important part of the website is its URL structure. web.py makes it easy to make great URLs.

<pre>
urls = (
'/', 'index'
)
</pre>

The first part is a [https://en.wikipedia.org/wiki/Regular_expression regular expression] that matches a URL, like /, /help/faq, /item/, etc. The parentheses say to capture that piece of the matched data for use later on. The second part is the name of a class to send the request to, like index, view, welcome,t story: http://faruk.akgul.org/blog/python-development-story-why-webpy/

[[#References|[3]]] pillars of python-six web frameworks: http://www.infoworld.com/article/2622836/application-development/pillars-of-python--six-python-web-frameworks-compared.html?page=2

[[#References|[4]]] Django vs flash vs pyramid https://www.airpair.com/python/posts/django-flask-pyramid

[[#References|[5]]] Form Validation: https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/Forms/Data_form_validation

[[#References|[6]]] Aaron swartz about web.py http://www.aaronsw.com/weblog/rewritingreddit

[[#References|[7]]] https://www.wikipedia.org/